Reader Writer Semaphore Design - Kernel Recipes 2024

Explore the intricacies of Reader Writer Semaphore (rwsem) design in Linux kernel during this 42-minute conference talk from Kernel Recipes 2024. Delve into the synchronization mechanism used for read-heavy sleepable critical sections, examining techniques like optimistic spinning, lock handoff, and non-spinnable approaches that balance performance and fairness for long-duration waiters. Investigate the impact of atomic contention during reader lock acquisition on container application scalability. Compare the current rwsem design with scalable alternatives such as perCPU reader-writer semaphores, analyzing their effects on reader-side scalability and writer performance. Learn about potential approaches to address writer-heavy problems with perCPU rwsem as presented by speaker Neeraj Upadhyay.